Moving users between clusters

I am trying to bring up a second cluster on my site (I have master which is also cluster1). I am able to provision new users on the new cluster with no issue, but I am not grasping moving users to the cluster (as my current cluster1 is having performance issues). Trying to use ljumover.pl (ljumover.pl -v "1 +active(14) to 2 1500") works for about 5 users then starts scrolling